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<TITLE>Magic-8.3 Command Reference</TITLE>
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<H1> <IMG SRC=graphics/magic_title8_3.png ALT="Magic VLSI Layout Tool Version 8.3">
     <IMG SRC=graphics/magic_OGL_sm.gif ALIGN="top" ALT="*"> </H1>

<H2>crashbackups</H2>
<HR>
Handle periodic backups during a layout editing session.
<HR>

<H3>Usage:</H3>
   <BLOCKQUOTE>
      <B>crashbackups </B>[<B>start</B>|<B>stop</B>|<B>resume</B>|<B>disable</B>]
      <BR><BR>
   </BLOCKQUOTE>

<H3>Summary:</H3>
      The <B>crashbackups</B> procedure enables or disables the
      periodic saving of crash recovery backup files.
      <B>crashbackups</B> or <B>crashbackups start</B> sets the
      timer for the first periodic save.  After the timer times
      out, backup file is generated and written in the system
      temporary directory, and the timer is reset.  By default,
      the backup interval is 10 minutes (600000 msec).  The
      interval can be changed by setting the value of Tcl variable
      <B>$Opts(backupinterval)</B> to the interval value in msec. <BR><BR>

      <B>crashbackups stop</B> removes the timer callback and thus
      prevents further writing of backup files.  Note that if
      crash recovery is stopped or started multiple times during
      a session, the same filename is used to save the data. <BR><BR>

      <B>crashbackups resume</B> resumes running interval backups if
      stopped using <B>crashbackups stop</B>.  If the interval backups
      have never been started, or have been disabled, this command
      does nothing. <BR><BR> 

      <B>crashbackups disable</B> stops running interval backups and
      resets to the state of never having started interval backups.
      <B>resume</B> will have no effect in this state, and <B>start</B>
      must be issued to start the interval backups again. <BR><BR>
   </BLOCKQUOTE>

<H3>Implementation Notes:</H3>
   <BLOCKQUOTE>
      <B>crashbackups</B> is implemented as a Tcl procedure in the
      "tools.tcl" script file.  It calls the magic command
      "<B>crash save</B>". <BR><BR>

      The crash backup interval is handled by the <B>itimer</B> system
      subroutine.  There is only one timer per process.  A timer is also
      used by some long-running commands such as <B>extract</B> to track
      progress, so the crash backups must necessarily be suspended when
      those commands are using the process timer.
   </BLOCKQUOTE>

<H3>See Also:</H3>
   <BLOCKQUOTE>
      <A HREF=crash.html><B>crash</B></A> <BR>
   </BLOCKQUOTE>

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<P><I>Last updated:</I> March 17, 2021 at 10:53am <P>
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